A usual sporting bicycle for cycling or road racing is adapted to mount a water-bottle at the bicycle frame, usually at the down tube, so that a cyclist can drink water therefrom during the bicycle's running.
The water-bottle comprises a body having a spout and cap. The body of the water-bottle is usually cylindrical with an outer diameter larger than the down tube diameter carrying the water-bottle. Such a water-bottle, when the bicycle is running, causes an air eddy current behind the same to thereby increase the air resistance against the bicycle.
The increased air resistance will hamper the high speed running efficiency particularly with a sporting bicycle and result in more fatigue to the cyclist.